1. Field of the Invention
The present invention generally relates to audio tone signaling devices and, in particular, to such signaling devices which employ multiple audio tones.
2. Statement of the Prior Art
Audio tone signaling devices are well known and widely used. Their application in electrical and electronic devices are too numerous to mention. Some of the purposes for which they are used to provide a signal are the existence of a condition, the end of an operating cycle, the end of a period of time, or as a reminder of something. In some instances, a signaling device will be used to signal just a single function and in other cases, it will be used to signal multiple functions. The signaling of multiple functions in some instances may be handled by the number and time duration of the pulses produced by a signaling device. However, with the growing complexity and applications of electronic systems, the number and type of functions which must be signalled are often too complex for the use of just a single frequency tone For example, safety reasons dictate that an emergency signal not have a sound which is similar to the simple condition indicator or time period indicator.